Life Span of Normal Human Platelets Tagged with Chromium51

2015 ◽  
pp. 364-368 ◽  
Author(s):  
Knut A. Aas ◽  
Frank H. Gardner
Keyword(s):  
Life Span ◽  
Human Platelets ◽  
Normal Human

Ticlopidine Facilitates the Deaggregation of Human Platelets Aggregated by Thrombin

1994 ◽  
Vol 71 (01) ◽  
pp. 091-094 ◽  
Author(s):  
M Cattaneo ◽  
B Akkawat ◽  
R L Kinlough-Rathbone ◽  
M A Packham ◽  
C Cimminiello ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Platelet Aggregation ◽  
Prostaglandin E1 ◽  
Human Platelet ◽  
Adenosine Diphosphate ◽  
Human Platelets ◽  
Before And After ◽  
Normal Human ◽  
Platelet Aggregates ◽  
Induced Aggregation

SummaryNormal human platelets aggregated by thrombin undergo the release reaction and are not readily deaggregated by the combination of inhibitors hirudin, prostaglandin E1 (PGE1) and chymotrypsin. Released adenosine diphosphate (ADP) plays an important role in the stabilization of thrombin-induced human platelet aggregates. Since ticlopidine inhibits the platelet responses to ADP, we studied thrombin-induced aggregation and deaggregation of 14C-serotonin-labeled platelets from 12 patients with cardiovascular disease before and 7 days after the oral administration of ticlopidine, 250 mg b.i.d. Before and after ticlopidine, platelets stimulated with 1 U/ml thrombin aggregated, released about 80–90% 14C-serotinin and did not deaggregate spontaneously within 5 min from stimulation. Before ticlopidine, hirudin (5× the activity of thrombin) and PGE1 (10 μmol/1) plus chymotrypsin (10 U/ml) or plasmin (0.06 U/ml), added at the peak of platelet aggregation, caused slight or no platelet deaggregation. After ticlopidine, the extent of platelet deaggregation caused by the same inhibitors was significantly greater than before ticlopidine. The addition of ADP (10 μmol/1) to platelet suspensions 5 s after thrombin did not prevent the deaggregation of ticlopidine-treated platelets. Thus, ticlopidine facilitates the deaggregation of thrombin-induced human platelet aggregates, most probably because it inhibits the effects of ADP on platelets.

Monoamine Oxidase and Other Mitochondrial Enzymes in Density Subpopulations of Human Platelets

1988 ◽  
Vol 59 (01) ◽  
pp. 029-033 ◽  
Author(s):  
K G Chamberlain ◽  
D G Penington
Keyword(s):  
Monoamine Oxidase ◽  
Protein Concentration ◽  
Close Correlation ◽  
Human Platelets ◽  
Mitochondrial Enzymes ◽  
Density Fractions ◽  
Percoll Gradients ◽  
Normal Human ◽  
The Mean ◽  
Very High

SummaryNormal human platelets have been separated according to density on continuous Percoll gradients and the platelet distribution divided into five fractions containing approximately equal numbers of platelets. The mean volumes and protein contents of the platelets in each fraction were found to correlate positively with density while the protein concentration did not differ significantly between the fractions. Four mitochondrial enzymes (monoamine oxidase, glutamate dehydrogenase, cytochrome oxidase and NADP-dependent isocitrate dehydrogenase) were assayed and their activities per unit volume were found to increase in a very similar monotonie fashion with platelet density. When MAO and GDH were assayed on the same set of density fractions the correlation between the two activities was very high (r = 0.94–1.00, p <0.001) and a similar close correlation was found between MAO and ICDH. The results support the hypothesis that high density platelets either have a higher concentration of mitochondria or have larger mitochondria than low density platelets.

The Effect of Adenosine Phosphates on the Spreading of Normal Human Platelets

1969 ◽  
Vol 21 (02) ◽  
pp. 373-379
Author(s):  
H Linker ◽  
H Reuter
Keyword(s):  
Human Platelets ◽  
Adenosine Phosphates ◽  
Normal Human ◽  
Platelet Functions

SummaryThe spreading of human platelets requires the presence of ADP as do other platelet functions. In the plasma of patients with a failure of release of ADP from the platelets the also decreased ability to spread can be normalized by exogenous ADP. AMP and ATP inhibit the spreading of platelets.

Relationship Between Mepacrine-Labelled Dense Body Number, Platelet Capacity to Accumulate 14C-5-HT and Platelet Density in the Bernard-Soulier and Hermansky-Pudlak Syndromes

1979 ◽  
Vol 42 (02) ◽  
pp. 694-704 ◽  
Author(s):  
F Rendu ◽  
A T Nurden ◽  
M Lebret ◽  
J P Caen
Keyword(s):  
Dense Body ◽  
Human Subjects ◽  
Human Platelets ◽  
Dense Bodies ◽  
Storage Organelle ◽  
Hereditary Disorders ◽  
Labelling Procedure ◽  
Normal Human ◽  
Hermansky Pudlak Syndrome ◽  
Bernard Soulier Syndrome

SummaryWe have used the mepacrine-labelling procedure to measure the dense body (serotonin storage organelle) content of the platelets of 2 hereditary disorders where abnormalities in dense body number were suspected. The platelets were incubated with mepacrine and examined by fluorescence microscopy. A mean number of 5.4 ± 0.8 (SD) dense bodies per platelet was calculated from the data obtained using platelets isolated from 40 normal human subjects. In contrast the platelets of 2 patients with the Bernard-Soulier syndrome contained an average of 14 and 17 labelled granules. This increase was associated with a much greater capacity of the platelets to accumulate 14C-5-HT. The opposite result was obtained using the platelets from 2 patients with the Hermansky-Pudlak syndrome which contained few granules labelled by mepacrine and took up less 14C-5-HT than normal human platelets. Centrifugation of the patients’ platelets on discontinuous sucrose gradients showed that the platelets of the 2 Bemard-Soulier patients were much denser than normal whereas a high proportion of low density platelets was observed in the Hermansky-Pudlak syndrome. These results further define the platelet abnormalities in the two syndromes and suggest that dense body number may be one of the factors governing platelet density.

Heparin-Induced Aggregation of Normal Human Platelets

1981 ◽  
Vol 46 (02) ◽  
pp. 570-570 ◽  
Author(s):  
Margaret R Mclean ◽  
Lawrence L Hause
Keyword(s):  
Human Platelets ◽  
Normal Human ◽  
Induced Aggregation

scholarly journals Diadenosine 5',5'''-p1,p4-tetraphosphate deficiency in blood platelets of the Chediak-Higashi syndrome

Blood ◽  
1985 ◽  
Vol 66 (3) ◽  
pp. 735-737 ◽  
Author(s):  
BK Kim ◽  
FC Chao ◽  
R Leavitt ◽  
AS Fauci ◽  
KM Meyers ◽  
...  
Keyword(s):  
Whole Blood ◽  
Marked Decrease ◽  
Blood Platelets ◽  
Human Platelets ◽  
Dense Granule ◽  
Atp Level ◽  
Dense Granules ◽  
Moderate Reduction ◽  
Normal Human ◽  
Chediak Higashi Syndrome

Abstract Diadenosine tetraphosphate (AP4A) is an unusual nucleotide found in a variety of cells, including platelets. It has been suggested that platelet AP4A is stored in the dense granules and is metabolically inactive. We have studied the AP4A content of blood platelets in two patients and three cattle with Chediak-Higashi syndrome (CHS), a hereditary platelet defect with dense granule deficiency. Acid-soluble extractions of whole blood and platelets were neutralized. The adenosine triphosphate (ATP) level was measured by luminescence technique. To measure the AP4A content, the neutralized extract was treated with phosphomonoesterase for removal of ATP. The AP4A content was then measured by coupling the phosphodiesterase and luciferase reaction. The AP4A content was 0.43 nmol/mg protein for normal human platelets and 0.004 nmol/mg protein for CHS platelets. The ATP/AP4A ratio was 67 for normal and 3,023 for CHS platelets. The whole blood AP4A was reduced by 89% in CHS patients who had only a slight decrease in ATP level (26% reduction). Similarly, bovine platelets with CHS showed a marked decrease of AP4A content and a moderate reduction of the ATP level. The platelet ATP/AP4A ratio was 351 and 3,133 for normal and CHS cattle, respectively. Results demonstrate a marked reduction of AP4A in CHS platelets and suggest that AP4A may be a useful marker for the measurement of dense granule content in platelets.

scholarly journals Identification of primary lysosomes in human megakaryocytes and platelets

Blood ◽  
1982 ◽  
Vol 59 (3) ◽  
pp. 472-481 ◽  
Author(s):  
ME Bentfeld-Barker ◽  
DF Bainton
Keyword(s):  
Electron Microscopy ◽  
Bone Marrow ◽  
Lysosomal Enzymes ◽  
Human Platelets ◽  
Variable Size ◽  
Golgi Region ◽  
Normal Human ◽  
The Subject ◽  
Cytoplasmic Maturation ◽  
Normal Human Bone Marrow

Abstract The presence of lysosomal enzymes in human platelets is well documented; the identity of the “lysosome,” however, has been the subject of some disagreement. In order to determine the time of appearance and subcellular localization of two lysosomal enzymes in megakaryocytes (MK) and platelets, we examined normal human bone marrow and blood by electron microscopy and cytochemistry. Acid phosphatase (AcPase) was present in the Golgi region in the youngest recognizable MK, as well as in those with a considerable degree of cytoplasmic maturation. Heavy reaction product was usually confined to one or two Golgi-associated cisternae and coated vesicles; other Golgi cisternae were sometimes lightly reactive. In mature MK, reaction product was limited to vesicles of variable size, but smaller than alpha-granules. Another lysosomal enzyme, arylsulfatase (AS), was localized in similar small vesicles in MK of all stages; it could not be demonstrated in the Golgi complex. Vesicles containing AS were also found in about 25% of platelet profiles, whereas vesicles containing AcPase were found in only about 15% of platelet profiles. The alpha-granules of all MK and platelets examined were negative for both enzymes. We conclude that the enzyme-containing vesicles in these cells constitute the lysosomes and that they are distinct from other platelet organelles. Since there was no evidence that they had participated in any digestive event, we believe that they are primary lysosomes, whose contents are secreted during platelet aggregation and the release reaction.

scholarly journals Brief Report: Vitamin B12 and Folate Activity in Normal Human Platelets

Blood ◽  
1968 ◽  
Vol 31 (2) ◽  
pp. 258-262 ◽  
Author(s):  
HARVEY J. WEISS ◽  
ALAN KELLY ◽  
VICTOR HERBERT
Keyword(s):  
Platelet Count ◽  
Vitamin B12 ◽  
Whole Blood ◽  
Human Platelets ◽  
Red Cells ◽  
Red Cell ◽  
Normal Human

Abstract The vitamin B12 and folate content of human platelets have been determined. The B12 concentration was sixfold that in red cells and one-sixth that in leukocytes. In normal whole blood, with a platelet count of 300,000 per cu. mm., the B12 activity contributed by platelets would be 6-21 pg. per ml. The contribution of platelets to the folate activity of normal whole blood averaged 0.4-1.7 ng. per ml. The folate activity in platelets was one-fifth that in an equal volume of red cells, but unlike red cell folate, was not increased by incubating platelet extracts with plasma.

Depressed Responsiveness To Adrenaline In Platelets From Apparently Normal Human Donors – A Familial Trait

1981 ◽  
Author(s):  
M C Scrutton ◽  
K R Bruckdorfer ◽  
R A Hutton
Keyword(s):  
Adenylate Cyclase ◽  
Platelet Function ◽  
Divalent Cation ◽  
Platelet Rich Plasma ◽  
Human Platelets ◽  
The Other ◽  
Stimulus Response ◽  
A 23187 ◽  
Phospholipid Classes ◽  
Normal Human

Decreased responsiveness to adrenaline has been observed in 5 out of approximately 150 apparently normal unrelated human donors. In 4 donors, familial studies have shown that this trait is inherited. Three of the donors, as well as their affected relatives, exhibit depressed responsiveness to collagen and vasopressin but normal responsiveness to ADP and thrombin in association with the decreased responsiveness to adrenaline. The other two affected donors exhibit normal responsiveness to most other agonists although in one instance depression of responsiveness to vasopressin and absence of a secretory response to ADP may be associated with the decreased adrenaline response.Normal responsiveness can be restored in all instances either by incubating the platelet-rich plasma at 20°C or by addition at 37°C of a low concentration of the divalent cation ionophore, A-23187. No such effect results from addition of an adenylate cyclase inhibitor. All affected platelets have normal ATP and ADP contents, cholesterol to phospholipid ratios, and composition of the phospholipid classes. Mixing experiments demonstrate the absence of a circulating inhibitor of platelet function and suggest that the defect resides in the platelets. We conclude that depressed responsiveness of human platelets to adrenaline may result from a defect in Ca2+ mobilisation to the cytosol. The observed selectivity in the agonists affected may indicate that the stimulus-response coupling pathways converge at the level of an increase in cytosolic Ca2+ concentration.

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